Viola wasn't her problem ..
I think it was Throckmorton. Throckmorton is just so comically upper-crust, she'd sound funny even if her first name was Mary or Anne.
My guess is Simon made the joke because by that time, Viola was out of fashion and maybe had a hillbilly or bumpkin vibe?
That's why I don't think Viola has come back. I knew one Viola, she was a bit older than me and was from a seriously backwoods white family in Oklahoma, though I think they originally came from Arkansas. She had a brother named Claude and a sister named Kitty-Sue. In a school full of kids named Jennifer and Angie and Chris and Matt, they definitely stuck out.
Before you criticize a man, walk a mile in his shoes. That way, when you criticize him, you're a mile away and you have his shoes!
Steve Martin